Zinc doping of different nanoparticles of TiO2 Sachtopore for improved elimination of the methyl orange by photocatalysis

Heterogeneous photocatalysis is an increasingly popular method used to decontaminate polluted water. Dyes have become one of the major sources of water pollution and methyl orange is one of the most commonly used dyes in the textile industries. The objective of this study was to remove MO and compare the efficiency of the synthesized photocatalysts. In the current work, photodegradation of methyl orange dye, selected as a pollutant model is carried out at room temperature in aqueous solution of Zn-doped TiO2. The photocatalysts tested in this study were prepared by coprecipitation method. The catalysts were characterized by XRD, TEM, SEM, EDS, and DRS, before proceeding to photodegradation. X-ray diffraction showed that samples are only composed of TiO2 anatase, except TiO2 P25, which contains some crystallites in the rutile form. According to TEM, all nanoparticles of the different photocatalysts have a spherical, clearly dispersed and fine morphology. A strong agglomeration is observed for TiO2 P25. Energy dispersive X-ray spectroscopy confirmed Zn doping by the presence of peaks attributed to zinc. The UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) shows a shift of absorption from the UV region to the visible light region and shows that all nanoparticles have very similar absorption thresholds, thus the doped catalysts are promising materials for the use of visible light. The obtained results during the study of the adsorption showed that the order of adsorbability varies in the following decreasing direction: TiO2 Sachtopore (ZnCl2/TiO2= 0.2%) > TiO2 Sachtopore (ZnCl2/TiO2= 0.1%) > pure TiO2 Sachtopore > TiO2 P25. The photodegradation kinetics was studied as a function of several parameters. A comparison of the degradation kinetics of methyl orange has shown that TiO2 P25 provides comparable performances to doped TiO2 Sachtopore at 0.2% of Zn. 1 g/L is the optimum concentration for all catalysts used. The synthesized nanomaterials showed good photodegradation ability in MO decomposition, as well as the results reveal that photocatalysis is a very suitable technique for the purification of water containing methyl orange.